This invention pertains to a fluid filter apparatus, and more particularly to generally triangular shaped filter cartridges adapted to be compactly disposed in a vessel to increase filtration capacity.
Typically, filtration apparatuses generally comprise a filter vessel of generally cylindrical shape containing a number of replaceable filter cartridges for filtering contaminants from a fluid. A typical filter cartridge comprises a filter medium or media, a support member for the medium, and an end cap on each end of the medium. These filter vessels are generally cylindrical shaped for ease of manufacturing, and a desired objective is to have as many replaceable filter cartridges as possible disposed therein to increase the filtration capacity of a vessel of given diameter.
Currently, most filter cartridges are also generally circular in shape, which has been dictated by the shape of the support member for the filter medium. Support members are required not only to withstand forces imposed by a differential fluid pressure transversely applied across the filter cartridges, but also the forces longitudinally applied by the device or mechanism for securely holding the filter cartridges in the vessel. Generally, these support members are in the form of a perforated tube, and are frequently assisted in providing support by a standpipe longitudinally disposed therein. The support member must be sufficiently strong to withsland the above-described transverse and longitudinal forces, and previously the most economical shape for a support member has been cylindrical, thereby resulting in the filter cartridges likewise being of generally cylindrical shape. Thus, if a user desires a filter vessel of specified diameter, then the number of filter cartridges is dictated thereby. Further, if a desired number of filter cartridges is specified so as to provide a desired filtration capacity, then the diameter of the filter vessel is dictated by the quantity and the overall diameter of the filter cartridges.
Clearly, one of the disadvantages of the above prior art filter apparatuses is that a filter vessel of specified diameter and specified filtration capacity may not be of sufficient size to house the requisite number of filter cartridges to provide the desired filtration capacity. For example, a typical filter vessel is one having a diameter of sixteen inches, and a typical filter cartridge is one having a diameter of six inches, and only four such filter cartridges can be suitably placed in such a vessel. If the four filtration cartridges are not adequate to provide the desired filtration capacity of such a size vessel, the apparatus will be unsatisfactory to the user.
Another disadvantage with the above filter apparatuses concerns the generally cylindrically shaped and thin-walled support members, which generally have low collapsing pressure thresholds, and therefore easily collapse under applied external pressures that exceed their thresholds. Circumventing this disadvantage requires the support member to be constructed with a thicker wall, thereby possibly necessitating decreasing the depth or thickness of the filter medium and its filtration capacity.
In view of the above, there clearly exists a need for filter cartridges having shapes that permit a greater number thereof to be housed within a filter vessel of specified diameter to provide a desired filtration capacity.